Draft device for mining machines



T. E. PRAY.

DRAFT DEVICE FOR MINING MACHINES.

- Pawnjued Apr. 4, 1922.

APPLICATION FILED NOV- 22, I920- UNITED STATES PATENT oFFica I THOMAS E. PRAY, OF CHICAGO, ILLINOIS, ASSIGNOR TO GOODMAN MANUFACTURING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

v DRAFT DEVICE FOR MINING MACHINES.

To aZZ to hem it may concern Be it known that I, THOMAS E. PRAY, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a Draft Device for Mining Machines, of which the following is a specification.

This invention relates to improvements in draft devices for coal mining machinesof theclass adapted to be moved along the face of a mine wall to cut a. horizontal kerf thereunder, and has for its principal object, to provide an improved means associated with a draft mechanism for controlling the height of the kerf.

My invention will best be understood by referring to the accompanying drawings, in which Figure 1 is a plan view of a mining machine provided with a preferred form of my invention.

Figure 2 is a side view of the same machine.

Figure 3 is a vertical cross section taken on line 33 of Figure 1, and showing'the draft control device in enlarged detail.

Figure 4 is a vertical cross section similar to Figure 3, but showing the'sheave in raised position.

Mining machines of the class shown herein, to illustrate the use of my invention, usually have as common features, a body portion A adapted to rest on the mine floor,

and a cutting element B extending longitudinally from the body portion suitable for cutting the kerf. The cutting element may comprise any suitable device for this purpose, as for instance a cutter bar 1, carrying a movable cutter chain as indicated by the dotted lines in Figure 1. Such machines are provided with a motor'mounted on the body portion A having driving connection with the cutting mechanism and also having driving connection with draft device-for moving the machine during its cutting operation. In the particular form of mining machine illustrated, the draft device comprises a cable drum 2, preferably mounted on the advance side of the mining machine, and rearwardly of the front end 3 of the body portion A. A flexible cable 4 or its equivalent, which is termed the feed rope, is adapted to be wound on the drum and is led about a sheave 5 and anchored at a distance from the machine.

Specification of Letters Patent. Patent d A 4 1922 Application filed November 22, 1920.

Serial No. 425,655.

In the operation of machines of the class described, it is often necessary to follow a rolling or unlevel mine floor in forming a kerf, and while so doing, the cutter bar 1 has a tendency to travel in the natural plane predetermined by its position when its ini tial cut is made under the coal. Furthermore, it sometimes occurs that the cutter bar becomes deflected upwardly from the mine floor as it is cutting, which deflection may be due to several causes, as for instance, on account of uneven hardness of the material to be cut, or on account of uneven degree of sharpness of the cutter bits which make up the cutter chain.

In the present invention, I provide means for controlling the height of the kerf by means of the adjustmentin height of the sheave 5 about which the draft device 4 is engaged. This sheave has heretofore been similarly positioned in machines of this class, but has been fixed on the machine substantially in the'horizontal plane of movement of the cutter chain about the cutter bar 1. In the novel device embodying the present invention, however, this sheave is rotatably mounted on a sleeve 6, having vertical adjustment on a spindle 7 extending upwardly from a boss 8 formed in the base plate 9 of the machine body. The sleeve 6 has a threaded bolt 10 extending axially through its upper end 11 and engaging the upper end of said spindle. An inset portion 7* of hardened metal is preferably provided on the upper end of said spindle to afford a bearing at this point. The upper end 11 of the sleeve 6 extends through a supporting bracket 12, attached to the side of the machine frame by anyv suitable means such as bolts 13, 13. Means are provided for maintaining said sleeve 6 against rotation, which may comprise a keylt seated in the spindle 7 and engaging in an oppositely disposed keyway or slot 15, extendinglongitudinally of the sleeve, or any other equivalent device for this purpose.

In the arrangement illustrated, it will be observed that the sheave and the mechanism associated therewith is mounted on an axis inclined toward the rear of the machine. This arrangement is provided so as to afford a substantially straight pull from the sheave to the bottom of the draft drum 2 which, in the machine illustrated, is below the horizontal plane of movement of the cutter portingface of the machine bo y, which V rolling floor.

normal height from the floor.

chain. It is manifest, however, that the sheave axis may be varied somewhat from the position shown de ending upon the arrangement of the dra t rope 2, and its associated operating mechanism.

The use and operation of my device is as follows: When the sleeve 6, and the sheave 5 carried thereby, are in their lowermost positions as illustrated in Figure 2, the sheave is substantially in horizontal alignment with the cutter bar. The draft rope 2 is trained about said sheave and is anchored at a distance from the machine preferably at or near the floor of the mine in the usual manner. The draft means thus advances the machine laterally along the mine wall as the cutter bar forms the kerf. The body portion A of machines of this type has a relatively narrow supporting face, so that said machlne body will tend to follow uneven or But as has been before suggested, the cutter bar has a tendency to follow in a uniform plane determined by its initial position in the coal. Consequently, when the machine is moved along an uneven or rolling surface, the cutter bar will have either a tendency to dig in, i. e., cut down towards the floor, orto rideup, i. e., cut at an angle away from the floor. The tendency to dig in is readily controlled b the suprests on the mine floorand guides the cutter bar upwardly to counteract the digging in tendency. In case the cutter bar starts to ride up the mine wall, however, the wei ht of themachine body has been found ine ectual in keeping the cutter bar at its \Vhcn this occurs, the forward end of the machine is raised with the cutter-bar, thereby causing anunnecessary strain on the machine, andits workin parts, as well as forming an uneven kerfeight. With the present invention, the machine may be returned to its normal cutting plane by manipulating the screw 10 by any suitable means such as a wrench so as to raise the sheave 5 to some such'position as showniniFigure 4. The draft rope 2 then exerts a pull from a point above the horizontal center line of the cutter chain, thereby tending to deflect the cutter bar downwardly. This manipulation of the bolt 10 may take place without loosening or slacking the draft rope, and if desired, while the machine is moving. The sheave maybe adjusted to any height until it becomes effective for the purpose of returning the cutting element to its normal height above the mine floor," and thereafter, the sheave may be again returned to its normal cutting position by reversing the action of the screw 10. Since the draft rope is usually anchored at the floor of the mine, and the sheave is also raised from its normal line I of tangency with respect to the cable drum,

a downward thrust is exerted upon the sheave and the latter will resume its normal position automatically. V

I claim as my invention:

1. In a mining machine having suitable mechanism forcutting a continuous kerf, in combination, a flexible draft means, a spindle mounted on the machine frame, a sleevemember mounted on said spindle, a guide carried by said sleeve, and adapted to be engaged by said draft means, a screw device affording relative longitudinal movement between said spindle and said sleeve, and means preventing the rotation of said sleeve on said spindle.

2. In a mining machine having suitable mechanism for cutting a continous kerf, in combination, a flexible draft means, a spindle mounted on the machine frame, a slee e mounted on said spindle, a sheave rotatably mounted on said sleeve and adapted to be engaged by said draft means, a screw device having threaded engagement with said sleeve and adapted to coact with said spindle to afford relative longitudinal movement between the two lastnamed elements, and means preventing the rotation of said sleeve on said spindle.-

3. In a mining machine having suitable mechanism for cutting a continuous kerf, in combination, a flexible draft means, a spindle mounted on the machine frame, a sleeve mounted on said spindle, a sheave rotatably mounted on said sleeve and adapted to'bo engaged by said draftmeans, a screw device having threaded engagement with said sleeve and adapted to coact with said spindle to afford relative longitudinal movement between the last named elements, supporting means engaging the exterior of said sleeve, and means preventing the rotation of said sleeve onsaid spindle. V

Signed at Chicago, Illinois, this 19th day of November, 1920. r r. V THOMAS E. PRAY. 

